Fluid pressure sensitive switch



FLUID PRESSURE SENSITIVE SWITCH Filed Aug. 23, 1950 INVENTOR. JOSEPH SCHWEISS BY ATTORNEY UNITED STATES PATENT OFFICE FLUID PRESSURE SENSITIVE SWITCH Joseph .Schwciss, St. Louis, Mo., assignor to Carter Carburetor Corporation, St. Louis, Mo., a corporation of'Delaware Y Application August..23, 1950, Serial No. 181,066

This invention relates to fluid pressure sensitive switch devices and consists particularly of a novel switch device which responds, for instance, to changes in the oil pressure of an in- 2 Claims (01. 2004s) her 5, applying compression spring 2| to the top of the bellows, and then screwing inner casing member 6 into position with the end of its side wall firmly bearing aga nst bellows base flange I8.

ternal combustion engine and which is consid- In operation of the device when used as an oil erably simpler than previous switches of this pressure safety switch in an internal combustion type. The switch has the further advantage that engine, the oil system is first connected to nipple it may be easily assembled and adjusted. 3. Wire [5 is then connected in the ignition sys- In the accompanying drawing which illustrates tem and terminal screw 1 I adjusted so that upon the invention: the application of the proper pressure, switch Fig. 1 is a vertical, transverse center section point 19 will engage terminal screw l l to close through the novel switch. an electrical circuit. When a lesser pressure ex- Fig. 2 is a similar section but showing the parts ists in the oil pressure system, switch point IS! in the process of assembly. will separate from terminal I l breaking the cir- The switch comprises, generally, a pair of cupcuit. shaped members 5 and B with their open ends If desired, the relationship of nipple 8 and facing each other and threadedly assembled by terminal I I may be reversed so that the switch means of a female thread on member 5 and a actuating fluid pressure will be applied to the male thread on member 6 to form acasing. The outside of the bellows. Also, another type of end wall i of member 5 is provided with a threadexpansible chamber element may be substituted, ed nipple 3 for attachment to the source of opersuch as a diaphragm with a piston or chamber ating fluid pressure as, for instance, the oil forming a movable wall thereof. The invention pressure system of an internal combustion enmay be modified in these and other respects as gine. The end wall 9, of member 5, preferably, iS will occur to those skilled in the art and the ex- Of a u ar Co to receiving a s embly elusive use of all modifications as come within the wrench. Mounted centrally within end wall 9 is scope of the appended claims is contemplated. a bushing l 6 of insulating material having a cen- I claim: tral, internal thread receiving a terminal screw 1. In a fluid pressure sensitive electrical switch ii. Screw H s p v W a 00 nut a device, comprising an outer casing member inh x e nal, W h receiving p t n Ha id R0 eluding a base portion formed with a medial inlet therewith, and a nut 13 on the reduce upp rp opening and a tubular wall portion, the inner tion thereof for attachment of a terminal clip i 4 fag-3 of Said base being substantially flat throughon the end of an electrical Wire 15 whi h m y out, said tubular wall portion being of uniform constitute a P fi O the igniliiOn System 05 internal diameter and provided with internal an internal combustion en i e threads at its upper end, an expansible chamber Wi in e Casing formed y members 5 and 5 element within said casing, said expansible chamis an e pan b e bellows 57 having a base flange ber element being of generally tubular corrugated it which rests against the inner face of wall '1. form d having laterally projecting annular e E d Of the Side Wall Of D member 5 bears base flange resting upon the inner flat face of the n t i flange and Secures the Same and 40 base of the outer casing member adjacent its bellow I i position Centered Within the Casing tubular wall and about the inlet opening, an inand with the interior of the bellows in communit l casing member of tubular form having a cation with pressure fitting 8. The movable in dosed upper end, t upper end of Said casing ner wall of the bellows is provided with a switch being fo m d with a laterally projecting annular terminal I8 opposing the end of terminal screw shoulder normally overlying the upper end face it which forms the cooperating switch point. of t outer h b t upper portion of said The assembly of easing members 5 and 6 is maininner casing being formed with an exteriorly tained by a lock nut .20 threadedly received on threaded area terminating at said outwardly proinner member 5. A coiled compression spring jecting flange and the bottom portion of said it is lod ed Within t e Casing between the end internal casing being of reduced diameter for free n of the bellows and the under surface Of longitudinal movement within the annular outupper end wall 5. er casing and between the casing and said expan- The switch device may be rather easi y aS- sible chamber, the bottom face of said internal sembled, as illustrated in Fig. 2, simply by fir casing being flat and of a diameter to overlie inserting the bellows Within outer casing memand engage t outer upper marginal surface of the flange of the expansible chamber to form a seal between the expansible chamber and the bottom face of the external casing, a coil spring member normally seating about the top marginal portion of the expansible chamber for engage ment with the inner face of the internal casing to resist the movement of the expansible chamber when the inner and outer casings are assembled, a contact element threaded through and insulated from the top of the inner chamber for adjustment with respect to the top of said expansible chamber, a contact point arranged medially of the expansible chamber and carried thereby, said contact point being in axial alignment with the adjustable contact element in the top wall of the outer casing, whereby said contacts are positioned for adjustment when the parts are assembled and said expansible chamber expands or contracts, and lock means carried by the threaded portion of the internal casing member for securing the casing members in position.

4 2. The structure of claim 1 characterized in that the top of the expansible chamber is provided with a vertical annular projection for centering the coil spring, the upper end of which seats in an annular groove in the inner face of the upper end of the inner casing.

JOSEPH SCHWEISS.

10 References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,464,307 Bowlus Aug. '7, 1923 15 1,908,088 Warner May 9, 1933 2, 11,168 Chansor Mar. 15, 1938 2,296,411 Wills Sept. 22, 1942 FOREIGN PATENTS 20 Number Country Date 460,738 Great Britain Feb. 3, 1937 

